I am also facing this issue with this 3.9.4 version.
When adding scripts to the Button click or using the Event trigger, it seems it is making weird things, trying to GetComponents. I am seeing the following errors in console:
Could not find method 'GetComponentsInChildren' on ModifyTargetTransform
UnityEngine.Debug:LogError(Object, Object)
EventDelegate:Cache() (at Assets/NGUI/Scripts/Internal/EventDelegate.cs:405)
EventDelegate:get_parameters() (at Assets/NGUI/Scripts/Internal/EventDelegate.cs:193)
EventDelegateEditor:Field(Object, EventDelegate, Boolean, Boolean) (at Assets/NGUI/Scripts/Editor/EventDelegateEditor.cs:143)
EventDelegateEditor:Field(Object, List`1, String, String, Boolean) (at Assets/NGUI/Scripts/Editor/EventDelegateEditor.cs:275)
UIEventTriggerEditor:DrawEvents(String, String, List`1, Boolean) (at Assets/NGUI/Scripts/Editor/UIEventTriggerEditor.cs:55)
UIEventTriggerEditor:OnInspectorGUI() (at Assets/NGUI/Scripts/Editor/UIEventTriggerEditor.cs:39)
UnityEditor.DockArea:OnGUI()
I cannot add any parameter to the function as before and when assigning a function to the event sometimes it gets changed or stuck in a certain function without being able to change it. I have tried to use functions that do not receive parameters but still I am facing those errors that point to the NGUI EventDelegate script.